Ball mill



.J. R. BALL BALL MILL Filed Sept. 14, 1925,

imme I atented Dec. 30, 1924.

UNITED Ares JOHN R. BALL, or penance, oononano.

BALL MILL.

Application filed September 14, 1923. Serial No. 662,683.

To all whom it may concern.

Be it known that I, JOHN B. BALL, a citizen of the United States, residing at Durango, in the county of La Plata and State of Colorado, have invented certain new and useful Improven'ients in Ball Mills; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to improvements in ball mills of the type employing a pair of grindingcylinders in communication with each other, one ofsaid cylinders having an inlet for the ore or the like to be ground, while the other cylinder is provided with an outlet.

One object of the invention is to provide a mill of the type set forth in which the communicating passage between the two grinding cylinders is of greater size than the inlet for the one cylinder and in which the outlet from the other cylinder is still greater in size than said passage, thus mak ing provision whereby the material may easily feed through the machine.

Another object is to provide a single driven shaft rotatably carrying a pair of grinding cylinders at its ends, whereby these cylinders are readily accessible in case they must be partially or totally disassembled for making repairs, it being unnecessary to molest the mounting and driving means of the cylinders by employing this construc tion, whereas when trunnions are employed at the ends of the cylinders rotatably mounted in bearings, it is necessary to dismantle the bearings and a greater part of the entire machine when only slight repairs are necessary to the cylinder or cylinders.

A still further object is to provide a screen across the inlet end of the passage which establishes communication between the two cylinders, whereby the material cannot leave the first cylinder until it has been ground to a predetermined degree of fineness.

With the foregoing in View, the invention resides in the novel subject matter hereinafter described and claimed, the description being supplemented by the accompanying drawing in which a side elevation of a ball mill constructed in accordance with my invention is shown, parts being broken away and in vertical section.

In the drawing above briefly described, the numerals 1 and 2 designate a pair of grinding cylinders which are carried by the opposite ends of a single shaft 3 having a pulley or other driving men'iber l atits center, said shaft being mounted rotatably in bearings 3 at opposite sides of said driving member. By thus mounting the two cylinders, it will be seen that they are readily accessible for total or partial disassembling, Whenever any repairs 118 necessary, such as installing new lining plates, with which grinding cylinders of this character are usually provided.

In the construction shown, the cylinder 1 is provided with an inlet neck 5 having a well known form of spiral feeder 6 at its outer end, the shaft 3 is of tubular form to establish communication from the cylinder 1 to the cylinder 2, and the latter is provided with an outlet neck 7. The internal diameter of the shaft 3 is preferably greater than the internal diameter of the neck 5 and similarly the internal diameter of the outlet neck 7 is greater than that of the shaft 3. This permits the material to more readily feed through the machine than if all of the passages for such material, were of the same diameter.

For the purpose of detaining the material in the cylinder 1, until it has been ground to a predetermined degree of fineness, I provide a coarse screen 8 at the inlet end of the tubular shaft 3. All material passing through this screen is fed by the helical rib 9, within the tubular shaft 3, into the cylinder 2 where it is more finely ground before being discharged through the outlet neck 7. The rib 9 is preferably carried by the inner periphery of a lining sleeve 10 which extends through the tubular shaft 3 and may be renewed from time to time when desired.

In the preferred form of construction, the ends of the shaft 3 are provided with outstanding annular flanges 11 which are secured by bolts 12 to similar flanges 13 on a pair of hubs 14 which extend from the inner ends of the cylinders 1 and 2. The lining 10 extends into these hubs and thus takes the strain from the connections between them and the shaft 3.

All parts which are. subjected to wear are preferably provided with linings which may be renewed from time to time and the lining of the outlet neck 7 is preferably provided with a helical rib for feedingthe discharging material therethrough.

By employing the construction shown or,

- tained from the details disclosed, they are preferably followed, but within the scope of the invention as claimed, numerous mlnor changes may be made.

I claim 2- 1. A mill comprising a pair of spaced coaxial grinding cylinders, the outer end of one of said cylinders being provided with an inlet for unground material, while the outer end of the other cylinder is formed with a final discharge for the ground material, bearing means between the two cylinders, and a single tubular drive shaft for said cylinders, co-axial with and secured to the inner ends of said cylinders and establishing communication between the same, said shaft being rotatable in said bearing means and forming therewith the sole supporting means for said cylinders, whereby the latter are fully accessible for disassembly when making repairs.

2. A mill comprising a tubular shaft having outstanding flanges on its ends, a pair of grinding cylinders each having a hollow said bearings and having'shoulders engag- 7 ing the same to hold the shaft against endwise movement, a driving wheel on the center of said shaft between said bearings, outstanding annular flanges at the ends of said tubular shaft, a lining tube snugly held within said tubular shaft and projecting beyond both ends thereof, a pair of axially alined grinding cylinders having hollow hubs at their inner ends into whichthe projecting ends of said lining tube extend, an-

nular flanges on the ends of said hubs cone tacting with the flanges of said tubular shaft, and bolts passing through the shaft and hub flanges to rigidly secure them together, one of said cylinders being formed with an inlet while the other is provided with an outlet. 7

In testimony whereof I have hereunto affixed my signature.

JOHN R. BALL. 7 I 

